In the NGN network or the IMS network, an application server (AS for short) is located on a core network for processing complicated service logic control. The performance of the application server is affected by the complexity of the service logic and the frequency of database access. As the processing capability of one application server is limited, when the traffic is increased continuously, the number of the application servers needs to be expanded so as to enhance the processing performance of the application server. From the perspective of the core network, an increase in the number of the application servers is bound to bring forth an increase in the number of the IP addresses for the application servers, and changes in the network topological structure and in the user distribution. If the processing capability of the application server can be improved without any modification of the configuration of the core network device, the problems of the performance bottleneck and the capacity expansion of the application server will be settled effectively. Thus, the present invention is proposed to settle these problems.